Gomez warned any younger fans who might want to see the film by American director Harmony Korine, in which the bikini-clad actresses rob tourists on Florida beaches, "Don't see it!"

At the same time, the 20-year-old defended her choice to star in the deliberately trashy film, which includes pornographically-shot nudity and lesbian frolicking, as her first foray into grown-up film-making.

"It's hard for people to take me seriously (in a highly sexualized and violent adult role) given the brand that I've been given, which I'm thankful for, but... people obviously put you in this little box," she told reporters at the Toronto International Film Festival, where the movie debuted Friday.

This role, Gomez said, "is not necessarily breaking out of anything. It's just me doing something that I really want to do. I'm super passionate about the acting part of what I do, and I just want to do stuff for me sometimes."

The one-time Disney darling acknowledged that it was a big risk, because "I do have a younger generation of fans that support me and mean a lot to me. Everything I do is for my fans.

"So when I took on this movie... I knew it wouldn't be very suitable for that generation," she said.

Gomez was discovered by the Disney Channel in a US-wide talent search in 2004, and went on to launch a singing career and a clothing line, but she is best known for her role in the Emmy Award-winning television series "Wizards of Waverly Place" and in the tabloids for dating pop icon Justin Bieber.

On her social networking site, Gomez urged young adults to see "Spring Breakers" because, as she said at the Toronto International Film Festival, "it is very real, it's not sugar coated."

But the star noted the film is rated R, meaning anyone under age 17 cannot attend without supervision, so "this movie is not for my littles ;)"

The plot revolves around four hedonistic girls -- played by Gomez, fellow Disney alumna Vanessa Hudgens, Ashley Benson and Rachel Korine, the director's wife -- who go to Florida for their spring break university holiday in a binge of drink, drugs and flesh.

Their fortunes take a turn for the worse when they are arrested and bailed out by James Franco's creepy gold-toothed gangster character, Alien.

Because Gomez, Hudgens and the rest of the cast have been working much of the young lives, they missed out on North America's annual March pilgrimage to Fort Lauderdale, Florida and other beach hotspots for tequila-fueled parties, sunbathing and sex.

Benson noted that extras in the film were actually on spring break. "It was insane. It definitely felt like I was on spring break for a month," she told a press conference.

Franco quipped: "All these thick neck jock dudes (were) trying to rub up on them all the time, trying to grind on Selena. It was pretty awesome."

The young actress confessed that, for the film, Korine "got us to do things that I didn't even think I was able to do."

For example, she said "I never believed I could smoke a bong."

The articulate and bright young woman laughed when Korine told reporters that he had hid all of the "crazy artwork" in his house before auditioning Gomez in his living room, saying "I didn't want to spook her."

Gomez commented, hinting at the real girl behind a carefully crafted image as America's sweetheart, "He thought I was like this super, super Christian. And he put away all of this art. I was like, 'If I was a Christian girl I probably wouldn't have done this movie with (him).'"